How to get border off?
Try dry stripping to get the top layer off and then soak it off with water which includes a little detergent or fabric softener. The problem may be that the border has been stuck on with pva or some other glue. The best method is steam stripping
Scoring also helps on "ordinary" paper if it's being difficult. You'd need to do this and then apply your water with a sponge repeatedly until lit eventually soaks in and softens the paper. You can also usually hire wallpaper removers, which operate with steam and are effective.
Is the border vinyl? Nothing soaks into vinyl. You have to score the surface of it--there is a special tool made just for that--so the wallpaper remover can get to the glue. You will probably have to get a corner loose, then tear off the vinyl part, then use the wallpaper remover on what's left. Once the paper is gone, you keep using the remover and scraper (carefully) and a cloth to get the rest of the glue off
wallpaper remover. sold at home improvement stores for a few bucks. two or three applications may be required. they'll also sell you something to patch the damaged wall you've already created.
Score it with a utility knife in a hash pattern, and then spray soapy water on it, repeat as needed. Then scrape it off with a putty knife. There may be some residual glue that needs cleaned off. Then touch up the drywall with some joint compound and sand it, to make a nice smooth wall. Two coats of finish paint will make it nice and you will never know it was there